There are in fact open source svg library sets that include all emojis. According to a websearch:
Code:
Popular Open-Source Emoji SVG Libraries
OpenMoji:
An open-source project designed specifically for designers and developers, offering over 4,000 standardized vector emojis under a Creative Commons license.
Twemoji (Twitter/X):
Twitter's open-source emoji graphics are widely available as standalone SVG files and packages.
Google Noto Emoji:
Google's extensive emoji library provides vector paths supporting the entire Unicode standard.
Microsoft Fluent Emoji:
A 3D/flat open-source collection from Microsoft available in vector formats.
svgmoji:
A utility and wrapper library that tracks major open-source emoji sets and bundles them as scalable SVG sprites.
Iconbuddy:
A massive free icon aggregator that indexes thousands of open-source SVG emojis from Noto, OpenMoji, and Fluent.
Given how few e-readers support emojis that use multiple codepoints, using one of these svg scalable images would be the way I would include them for general accessibility.
Calling images text, was a mistake by the Unicode standard in my opinion.
It is like in the old days when zapf dingbats used glyphs to create images.